Most steel billets of circular, square, and rectangular cross-sections are produced on continuous casting plants. One of the most wide-spread internal defects of a continuous ingot is axial porosity accompanied by impurity segregation arising at bulk crystallization of the axial zone of the liquid core of the ingot.
Electromagnetic stirring of the liquid core using rotating magnetic fields (RMF) at the mold level practically does not affect the process of axial porosity formation. RMF application in the lower part of the liquid core of the ingot, at the strand level, is ineffective due to a high viscosity of the overcooled melt, because of a high concentration of solid nuclei (crystallization centers) in the melt and large thickness of the solid phase, which requires a considerable increase in the power of RMF inductors.
If billets possess axial porosity, the quality of products obtained by plastic deformation cannot be guaranteed. Therefore, the elimination of this flaw is an important technological problem.
The efficiency of previous attempts to solve this problem by various methods (e.g., by exciting ultrasonic oscillations using an additional RMF inductor or by exciting low-frequency oscillations of the melt using RMF inductors) were insufficient. It is therefore an object of the invention to provide a method for eliminating axial porosity accompanied by impurity segregation arising at bulk crystallization of the axial zone of the liquid core of a continuous ingot.